How to get old Mapping and Voronoi nodes into Blender 2.82?
Good news. Blender will automatically convert these old nodes for you.
Just get an older Blender version and copy/paste them.

Download Blender 2.80 and create your material.
Make sure the nodes are connected (or it won't work).
Copy/paste an object with the  material into Blender 2.82, the nodes will be converted.